Energy Efficient Engine: Flight propulsion system final design and analysis

The Energy Efficient Engine (E3) is a NASA program to create fuel saving technology for future transport engines. The Flight Propulsion System (FPS) is the engine designed to achieve E3 goals. Achieving these goals required aerodynamic, mechanical and system technologies advanced beyond that of current production engines. These technologies were successfully demonstrated in component rigs, a core engine and a turbofan ground test engine. The design and benefits of the FPS are presented. All goals for efficiency, environmental considerations, and economic payoff were met. The FPS has, at maximum cruise, 10.67 km (35,000 ft), M0.8, standard day, a 16.9 percent lower installed specific fuel consumption than a CF6-50C. It provides an 8.6 percent reduction in direct operating cost for a short haul domestic transport and a 16.2 percent reduction for an international long distance transport

PHYSICS-BASED SHAPE MORPHING AND PACKING FOR LAYOUT DESIGN

The packing problem, also named layout design, has found wide applications in the mechanical engineering field. In most cases, the shapes of the objects do not change during the packing process. However, in some applications such as vehicle layout design, shape morphing may be required for some specific components (such as water and fuel reservoirs). The challenge is to fit a component of sufficient size in the available space in a crowded environment (such as the vehicle under-hood) while optimizing the overall performance objectives of the vehicle and improving design efficiency. This work is focused on incorporating component shape design into the layout design process, i.e. finding the optimal locations and orientations of all the components within a specified volume, as well as the suitable shapes of selected ones. The first major research issue is to identify how to efficiently and accurately morph the shapes of components respecting the functional constraints. Morphing methods depend on the geometrical representation of the components. The traditional parametric representation may lend itself easily to modification, but it relies on assumption that the final approximate shape of the object is known, and therefore, the morphing freedom is very limited. To morph objects whose shape can be changed arbitrarily in layout design, a mesh based morphing method based on a mass-spring physical model is developed. For this method, there is no need to explicitly specify the deformations and the shape morphing freedom is not confined. The second research issue is how to incorporate component shape design into a layout design process. Handling the complete problem at once may be beyond our reach,therefore decomposition and multilevel approaches are used. At the system level, a genetic algorithm (GA) is applied to find the positions and orientations of the objects, while at the sub-system or component level, morphing is accomplished for select components. Although different packing applications may have different objectives and constraints, they all share some common issues. These include CAD model preprocessing for packing purpose, data format translation during the packing process if performance evaluation and morphing use different representation methods, efficiency of collision detection methods, etc. These common issues are all brought together under the framework of a general methodology for layout design with shape morphing. Finally, practical examples of vehicle under-hood/underbody layout design with the mass-spring physical model based shape morphing are demonstrated to illustrate the proposed approach before concluding and proposing continuing work

Non-Contact Height Estimation for Material Extrusion Additive Systems via Monocular Imagery

Additive manufacturing is a dynamic technology with a compelling potential to advance the manufacturing industry. Despite its capacity to produce intricate designs in an efficient manner, industry still has not widely adopted additive manufacturing since its commercialization as a result of its many challenges related to quality control. The Air Force Research Laboratory (AFRL), Materials and Manufacturing Directorate, Functional Materials Division, Soft Matter Materials Branch (RXAS) requires a practical and reliable method for maintaining quality control for the production of printed flexible electronics. Height estimation is a crucial component for maintaining quality control in Material Extrusion Additive Manufacturing (MEAM), as the fundamental process for constructing any structure relies on the consecutive layering of precise extrusions. This work presents a computer vision solution to the problem of height estimation using monocular imagery as applicable to MEAM

Evaluating the utility of multi-user VR in product development

Verifying the design of a mechanical product typically requires a physical mockup. Virtual reality can avoid this by letting workers experience real-size design inspections avoiding to waste time and money to produce physical and potentially still faulty assets. Multi-user environments have been studied to verify the utility of virtual reality in performing design reviews for maintainability. The main features required in such software have been determined. A systematic literature review on the state of the art usages of virtual reality for design inspections and industrial training completes the thesis

Reliability analysis for systems with outsourced components

The current business model for many industrial firms is to function as system integrators, depending on numerous outsourced components from outside component suppliers. This practice has resulted in tremendous cost savings; it makes system reliability analysis, however, more challenging due to the limited component information available to system designers. The component information is often proprietary to component suppliers. Motivated by the need of system reliability prediction with outsourced components, this work aims to explore feasible ways to accurately predict the system reliability during the system design stage. Four methods are proposed. The first method reconstructs component reliability functions using limited reliability data with respect to component loads, and the system reliability is then estimated statistically. The second method applies two-class support vector machines (SVM) to approximate limit-state functions of outsourced components based on the categorical reliability dataset. With the integration of the obtained limit-state functions and those of in-house components, the joint probability density function of all the components is estimated, thereby leading to accurate system reliability prediction. The third method is an extension of the second one, and a one-class SVM is proposed to rebuild limit-state functions for outsourced components given only the failure dataset. The last method deals with the case where no reliability dataset is available. A partial safety factor method is developed, which enables component suppliers to provide sufficient information to system designers for accurate reliability analysis without revealing the proprietary design details. Both numerical examples and engineering applications demonstrate the accuracy and effectiveness of the proposed methods --Abstract, page iv

A Conceptual Framework to Support Natural Interaction for Virtual Assembly Tasks

Over the years, various approaches have been investigated to support natural human interaction with CAD models in an immersive virtual environment. The motivation for this avenue of research stems from the desire to provide a method where users can manipulate and assemble digital product models as if they were manipulating actual models. The ultimate goal is to produce an immersive environment where design and manufacturing decisions which involve human interaction can be made using only digital CAD models, thus avoiding the need to create costly preproduction physical prototypes. This paper presents a framework to approach the development of virtual assembly applications. The framework is based on a Two Phase model where the assembly task is divided into a free movement phase and a fine positioning phase. Each phase can be implemented using independent techniques; however, the algorithms needed to interface between the two techniques are critical to the success of the method. The paper presents a summary of three virtual assembly techniques and places them within the framework of the Two Phase model. Finally, the conclusions call for the continued development of a testbed to compare virtual assembly methods